Police revealed further details on Friday of the shocking conditions in which their three alleged victims were kept.

The women, a 69-year-old from Malaysia, a 57-year-old from Ireland and 30-year-old Briton, were allegedly subjected to decades of physical abuse and beatings after being brainwashed by their captors.

Detective Inspector Kevin Hyland of the Metropolitan Police’s human trafficking unit said: “Whilst we do not believe that they have been subjected to sexual abuse, we know that there has been physical abuse, described as beatings - however there is nothing to suggest that the suspects were violent towards others outside of the address.”

The youngest of the women has spent her entire life in the house, but is understood to have had some form of basic education.

The three women were only allowed to leave their house under carefully controlled circumstances and were said to be terrified of their captors.

But detectives explained that far from living in isolation, the group were probably known to the authorities including social services.

It has also been reported that one of the women was denied medical attention after suffering a stroke while inside the house.

Commander Steve Rodhouse from the Metropolitan Police said: “We believe at this stage to the outside world this may have appeared to be a 'normal' family.

“This does mean that over the course of many decades the people at the heart of this investigation and their victims will probably have come into contact with public services, including our own, that is something we must examine fully, and it is too early to provide details.”

He added: “What I can say with some certainty is that the two suspects in the case were arrested by the Metropolitan Police in the 1970s , some considerable time ago.”

A spokesman for Lambeth Council refused to discuss whether social services had any contact with the group.

Police were tipped off about the case by the Freedom charity when the 57-year-old women plucked up the courage to report her ordeal after watching a news report about modern slavery.

Specially trained charity workers spent several days winning her trust before she and the younger woman escaped on October 25 to a pre-arranged location where they were met by waiting police officers.

Detectives then returned to the house and removed the eldest woman to safety.

Almost a month went by before the two alleged captors were arrested by officers from the Met’s Human Trafficking Unit.

On Friday officers who have spent years investigating the growing scandal of slavery and domestic servitude admitted that this case was completely “unique” in their experience.

Mr Rodhouse said what his officers had uncovered was a “complicated and disturbing picture of emotional control over many years”.

He said to many in the outside world the group may have appeared to be an ordinary family in an ordinary house which might explain why it went under the radar for so long.

Describing the circumstances in which the three alleged victims were held, Mr Rodhouse said: “It is not as brutally obvious as women being physically restrained inside an address and not being allowed to leave.”

DI Hyland said 37 officers were working on the case and had removed 55 bags of evidence and 12,500 exhibits from the “ordinary” looking house.

Police also confirmed that they had been in contact with officials in Malaysia and Ireland.

DI Hyland said: “We are unpicking a story that spans at least 30 years of these women's lives, and all of this requires police activity to turn that into evidence.”

The two people arrested are understood to be of Asian origin and have also been arrested on suspicion of immigration offences.